streaming is obviously going to be a game changer - it's clear to any non-luddite
but the market will be hard to predict - i think it's going to be xCloud and a dark horse AWS solution duking it out in 3 years
I think xCloud has the best chance of currently-known options, including whatever Amazon tries. Microsoft have the backend infrastructure to do it right, but more importantly xCloud is going to offer the kind of flexibility and choice necessary to get people to dip their toes into streaming. You can have a console for home, and xCloud on the road. You can use streaming as much or as little as you want, and lose nothing. And perhaps most importantly, being an extension of the Xbox ecosystem instead of a new ecosystem, it means you're getting the full gamut of new release games plus exclusives.
It's not like Stadia where you have to buy in all the way - your friends aren't following you, nor are your purchases, nor are your saves, nor is anything else. And if you decide Stadia streaming isn't for you, nothing you left there is going to follow you elsewhere..